UI buttons on a panel not working

I can open up this panel and close it just fine with a separate button, but the four buttons on this panel are completely non-responsive. I have an EventSystem and I believe all the buttons are correctly linked to where they should be.

Code (CSharp):

1. public GameObject chao;
2.     public GameObject chaoPanel;
3.     public GameObject[] chaoList;
4. void Start()
5.     {
6.         if (!PlayerPrefs.HasKey("looks"))
7.         {
8.             PlayerPrefs.SetInt("looks", 0);
9.             createChao(PlayerPrefs.GetInt("looks"));
10.         }
11.     }
12. public void buttonBehavior (int i)
13.     {
14.         switch(i)
15.         {
16.             case (0):
17.             default:
18.                 chaoPanel.SetActive(!chaoPanel.activeInHierarchy);
19.                 break;
20.             case (1):
21.                 break;
22.             case (2):
23.                 break;
24.             case (3):
25.                 if (MusicPlayer.GetComponent<AudioSource>().isPlaying)
26.                 {
27.                     MusicPlayer.GetComponent<AudioSource>().Pause();
28.                 }
29.                 else
30.                 {
31.                     MusicPlayer.GetComponent<AudioSource>().UnPause();
32.                 }
33.                 break;
34.             case (4):
35.                 chao.GetComponent<Chao>().saveChao();
36.                 Application.Quit();
37.                 break;
38.         }
39.     }
40.     public void createChao (int i)
41.     {
42.         if (chao)
43.         {
44.             Destroy(chao);
45.             chao = Instantiate(chaoList[i], new Vector3(0,0,-2), Quaternion.identity) as GameObject;
46.         }
47.         if (chaoPanel.activeInHierarchy)
48.             chaoPanel.SetActive(false);
49.         PlayerPrefs.SetInt("looks", i);
50.     }

 

Do the buttons have OnClick events set to this script? Are they calling 'buttonBehaviour' and passing an integer?
Is this script on an object in the scene?
Anything else - maybe I misunderstood?

 

Yeah they are all calling buttonBehavior and linked to a function in the script. That's why I'm so confused. I have other buttons set up just like them from what I can see and they work just fine.

 

Ya, that doesn't sound good/right.. Not sure what else to say if you believe everything is setup correctly.